In this sense they proved that the Yamabe problem (REF )
is stable with respect to the perturbations from below of the linear
term. Also, they showed blow up phenomena -and so instability- with
other choiches of perturbation of linear term. After them, the stability
vs. instability of (REF ) has been studied by several authors.
We limit ourselves to cite [1]}, [2]}, and [3]}. In the
last paper a sharp description of the blow up profile for solutions
of perturbed problem is given.
